I'd like to firstly say thank you very much to Denford for making ALL or at least HUGE amounts of information available via PDF. Without it I would have been reluctant to jump in blind to a lathe upgrade {update}. Looking for an old Denford cnc mill now
{I've an FB2 EMCO, which I keep thinking about converting to CNC, so looking for something similar capacity wise, suggestions would be most welcome on what to lookout for}________________________________
Ok, the ORAC has a motor pulley OD of 35mm, and a spindle pulley OD of 63mm, so the drive ratio is ~1.8:1
The motor is 4 pole, and at UK 50hz, that would put motor speed at ~1400 rpm at ~7~6% slip.
The ORAC was advertised as "Spindle Speed (stepless) 0-2000rpm"
At 1.8:1 pulley ratio, this would put the motor rpm at ~3600 rpm (ok, I have not measured the pulley circular pitch, just the OD)
That implies that the motor would need to be run at ~120Hz minimum (allowing for 6~7 slip) bumps that up to ~128 hz
Question 1: Does anyone know what the original Orac VFD runs / ran at maximum frequency wise?
Question 2: Does anyone know what the original Orac VFD carrier wave runs / ran at?
I came across this post, but was not sure if the manual contained here was actually for the ORAC as it did not quite seem the same the the VFD board I removed viewtopic.php?f=43&t=1243
Thanks
Rob
